.TH std::is_array 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::is_array \- std::is_array

.SH Synopsis
   Defined in header <type_traits>
   template< class T >              \fI(since C++11)\fP
   struct is_array;

   std::is_array is a UnaryTypeTrait.

   Checks whether T is an array type. Provides the member constant value which is equal
   to true, if T is an array type. Otherwise, value is equal to false.

   If the program adds specializations for std::is_array or std::is_array_v, the
   behavior is undefined.

.SH Template parameters

   T - a type to check

   Helper variable template

   template< class T >                                     \fI(since C++17)\fP
   inline constexpr bool is_array_v = is_array<T>::value;



Inherited from std::integral_constant

.SH Member constants

   value    true if T is an array type, false otherwise
   \fB[static]\fP \fI(public static member constant)\fP

.SH Member functions

   operator bool converts the object to bool, returns value
                 \fI(public member function)\fP
   operator()    returns value
   \fI(C++14)\fP       \fI(public member function)\fP

.SH Member types

   Type       Definition
   value_type bool
   type       std::integral_constant<bool, value>

.SH Possible implementation

   template<class T>
   struct is_array : std::false_type {};

   template<class T>
   struct is_array<T[]> : std::true_type {};

   template<class T, std::size_t N>
   struct is_array<T[N]> : std::true_type {};

.SH Example


// Run this code

 #include <array>
 #include <iostream>
 #include <type_traits>

 class A {};

 int main()
 {
     std::cout << std::boolalpha;
     std::cout << std::is_array<A>::value << '\\n';
     std::cout << std::is_array<A[]>::value << '\\n';
     std::cout << std::is_array<A[3]>::value << '\\n';
     std::cout << std::is_array<float>::value << '\\n';
     std::cout << std::is_array<int>::value << '\\n';
     std::cout << std::is_array<int[]>::value << '\\n';
     std::cout << std::is_array<int[3]>::value << '\\n';
     std::cout << std::is_array<std::array<int, 3>>::value << '\\n';
 }

.SH Output:

 false
 true
 true
 false
 false
 true
 true
 false

.SH See also

   is_bounded_array   checks if a type is an array type of known bound
   (C++20)            \fI(class template)\fP
   is_unbounded_array checks if a type is an array type of unknown bound
   (C++20)            \fI(class template)\fP
   rank               obtains the number of dimensions of an array type
   \fI(C++11)\fP            \fI(class template)\fP
   extent             obtains the size of an array type along a specified dimension
   \fI(C++11)\fP            \fI(class template)\fP
   remove_extent      removes one extent from the given array type
   \fI(C++11)\fP            \fI(class template)\fP
   remove_all_extents removes all extents from the given array type
   \fI(C++11)\fP            \fI(class template)\fP
